net: dsa: bcm_sf2: Allow matching arbitrary IPv4 mask lengths

There is no reason why we should limit ourselves to matching only full
IPv4 addresses (/32), the same logic applies between the DATA and MASK
ports, so just make it more configurable to accept both.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>